Ji-Hun Kang1, Da-Woon Jung1, Kyoung-June Pak2, In-Ju Kim3, Hak-Jin Kim4, Jae-Keun Cho5, Sung-Chan Shin1, Soo-Geun Wang1, Byung-Joo Lee1. 1. Department of Otorhinolaryngology-Head and Neck Surgery, Pusan National University School of Medicine, Pusan National University, Busan, South Korea. 2. Department of Nuclear Medicine, Pusan National University School of Medicine, Pusan National University, Busan, South Korea. 3. Department of Internal Medicine, Pusan National University School of Medicine, Pusan National University, Busan, South Korea. 4. Department of Radiology, Pusan National University School of Medicine, Pusan National University, Busan, South Korea. 5. Department of Otorhinolaryngology-Head and Neck Surgery, Inje University Ilsan Paik Hospital, Ilsan, South Korea.
Abstract
BACKGROUND: Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (18 F-FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole-body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of 18 F-FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of 18 F-FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results. METHODS: Sixty-six patients with locoregional recurrent PTC who underwent 18 F-FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of 18 F-FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow-up was also reviewed, and survival probabilities were estimated using the Kaplan-Meier plot. RESULTS: The sensitivity, specificity, and diagnostic accuracy of 18 F-FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of 18 F-FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease-free survival times were 33.3 months and 81.8 months, respectively (P < .001). CONCLUSION: The diagnostic value of 18 F-FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, 18 F-FDG PET/CT should be considered for prognostication rather than diagnosis.
BACKGROUND:Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (18 F-FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole-body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of 18 F-FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of 18 F-FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results. METHODS: Sixty-six patients with locoregional recurrent PTC who underwent 18 F-FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of 18 F-FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow-up was also reviewed, and survival probabilities were estimated using the Kaplan-Meier plot. RESULTS: The sensitivity, specificity, and diagnostic accuracy of 18 F-FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of 18 F-FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease-free survival times were 33.3 months and 81.8 months, respectively (P < .001). CONCLUSION: The diagnostic value of 18 F-FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, 18 F-FDG PET/CT should be considered for prognostication rather than diagnosis.
Authors: Se Jin Cho; Chong Hyun Suh; Jung Hwan Baek; Sae Rom Chung; Young Jun Choi; Jeong Hyun Lee Journal: Eur Radiol Date: 2019-02-26 Impact factor: 5.315